Vehicle brake



April 11, 1939. e. c. R. KUIPER VEHICLE BRAKE 2 Sheets-Sheet 1 Filed Sept. 21, 1936 INVENTOR.

6EE//%D Cf. Au/PE/E' BYZ A ORNEY.

April 1 1, 1939. ca. c. R, KUIPER VEHICLE BRAKE 2 Sheets-Sheet 2 Filed Sept. 21, 1956 INVENTOR. Glrex/meo 6J6, lam 5F ATTORNEY Patented Apr. 11, 1939 UNITED STATES VEHICLE BRAKE Gerhard O. K. Kuiper, Cleveland, Ohio, assignor to The Midland Steel Products Company,

Cleveland, Ohio, a. corporation of Ohio Application September 21, 1936, Serial No. 101,719

11 Claims.

This invention relates to new and useful improvements in vehicle brakes and an object of the invention is to provide a compensating relay valve for controlling the operation of the trailer 5; brakes.

Another object of the invention is to provide a compensating valve having a plurality of pressure responsive means of different effective areas for actuating the valve.

A further object of the invention is to provide a compensating valve having a plurality of pressure responsive means defining an actuating chamber therebetween to operate the valve, to thereby eliminate the necessity of springs to operate the valve.

Other objects and advantages of the invention will become apparent during the course of the following description.

In the accompanying drawings forming a part of the description and wherein like numerals are employed to designate like parts throughout the several views:

Fig. 1 is a sectional view of the compensating valve taken on the line of Fig. 2, 25 Fig. 2 is an end elevational view of the compensating valve, and

Fig. 3. is a tractor-trailer brake system embodying the compensating valve.

' Referring more particularly to Figs. 1 and 2, the numeral l0 designates a compensating relay valve comprising a housing formed in three sections I2, and I3 secured together near the marginal edges of two diaphragms l4 and I5 which divide the housing into three chambers l6, H and I8. Extending longitudinally of the housing section I3 is a bore l9 having a reduced portion communicating with the chamber l8 at one end and with an enlarged portion 2| at its other end. Asleeve 22 connected to a source 40 of suction, such as the intake manifold of an internal combustion engine is screwed into the enlarged portion 2| of the bore. This housing is also provided with a lateral port 23 communicating with the reduced portion of the bore l9 and with a breather 24 communicating with the atmosphere. Another lateral port 25 communicates with the enlarged portion of the bore |9 near its juncture with the portion 20 and with a chamber 3| of a power cylinder 26 to be later described.

55 chamber 3| of the power cylinder.

A by-pass 30 extends from the chamber I8 to the At the shoulder formed by the reduction in the diameter of the bore I9 is an annular recess in which is disposed a resilient seat member 32 having its inner peripheral surface in line with the surface of the reduced bore 20 and having a part of its flat side displaced to provide a resilient valve seat 33. Another annular resilient member 34 is disposed in the large bore 2| against the sleeve '22 and has one side exposed to provide a resilient valve seat 35.

Reciprocally mounted in the bore I9 is a spool type valve 40 for controlling communication of atmosphere between the port 23 and the power cylinder port 25 and is provided at its outer end with an enlarged annular closure or valve 4| which slidably engages the large bore 2| in substantially air tight fashion. This closure 4| has an annular valve portion 42 which engages the resilient valve seat 33. Adjacent the opposite end of the spool 40 is another annular closure 43 which slidably engages the reduced bore 20 in substantially air tight fashion. The annular closures 43 and 4| define therebetween an annular recess 44 which at all times spans the atmosphere port 23 irrespective of the position of the valve 40. Secured to the valve 40 is a cupshaped packing 45 having its marginal annular flange in air tight engagement with the reduced bore 20. 1

Another valve device is disposed in the enlarged bore 2| to control communication between the manifold port 22 and the power cylinder port 25. This valve device comprises a disk 5| having an annular flange smaller than the bore 2| to provide a valve 52 engageable with the resilient valve seat 35 and has a valve stem 53 slidably mounted in a bore 54 in the spool valve 40. A spring 55 interposed between the valve 5| and the valve 40 permits relative movement between these valves. Movement of the auxiliary valve 5| away from the spool valve 40 is limited by an enlarged head 51 at the end of the valve stem 53 abutting against a shoulder 56 formed by a reduction in the diameter of the bore 54.

. The pressure responsive means for operating the valves 40 and 5| comprise the diaphragms l4 and I5 which are secured to the inner end of the valve 40 by means of a stud 60 threaded into the bore 54. The diaphragm I5 is spaced away from the packing 45 by a spacer 6| which serves in clamping the packing 45 in the spool valve, and the diaphragms l4 and I5 are spaced from each other by a washer 62. It will be noted that a clamping plate 63 of relatively small diameter is disposed on one side of the diaphragm |5. The

effective diameter of the latter will therefore be approximately the distance between the lines 64 on the diaphragm I5. A clamping plate 65 of relatively large diameter is arranged on one side of diaphragm I4, making its effective diameter approximately the distance between the lines 66 on the diaphragm I4. Since the efiective diameter of diaphragm I5 is less than the efiective diameter of diaphragm I4, the latter will predominate over the diaphragm I5 and will tend to move the valves 40 and 5I in the direction where the differential pressure on the diaphragm I4 is greatest. The pressure in the chamber I'I between the diaphragms I4 and I5 is at all times at atmospheric pressure because the sectional housing I2 is provided with a plurality of ports 10 spaced circumferentially and exposed to the atmosphere through an air cleaner disposed in spaced relation about the periphery of the housing sections II, I2 and I3 and retaining filtering material over the ports.

The sectional housing I I is provided with a port II which communicates in a suitable manner with an operator operated control valve to subject the diaphragm I4 exposed in the chamber I6 to the differential pressures admitted to the latter by manipulating the control valve.

This relay valve is employed in the tractortrailer brake system illustrated in Fig. 3 herein shown as comprising a tractor 15 provided with a vacuum suspended brake system having a vacuum suspended power cylinder 16 closed at both ends and is provided with a piston 11 having a piston rod I8 connected to an arm 19 fixed to a rock shaft having at its opposite ends, a brake arm 8| connected to wheel brake mechanism not shown, for the tractor wheels 82. The piston 11 defines chambers 83 and 84 in opposite ends of the power cylinder 16; the chamber 83 communicating with the intake manifold 85 through conduits 86 and 81 for its source of suction. The other chamber 84 is connected to the source of suction through conduits 88 and 89, control valve 90 of the type for example, shown on my co-pending application Serial No. 78,870 filed May 9, 1936, and then through the conduits 86 and 81 to the manifold 85. The control valve 90 is operated by a foot pedal 9I having a lost motion connection with a link 92 in a manner described in the aforesaid application, and is connected to the rock shaft 80. A retractor spring 92' is connected to the arm I9 of cross shaft 80 to urge the brake system to brake release position.

This tractor brake system is connected to a trailer 95 having a vacuum suspended brake system comprising the power cylinder 26 closed at both ends and is provided with a piston 96 having a piston rod 91 connected to an arm 98 fixed to a rock shaft 99 having at its opposite ends a brake arm I00 connected to the wheel brake mechanism, not shown, of the trailer wheels IOI. The piston 96 defines chambers 3| and I02 at opposite ends of the power cylinder 26; the chamber 3I communicating with the power cylinder port 25 of the compensating relay valve I0. The chamber I02 communicates with the source of suction through a conduit I03, reservoir I04, conduit I05, coupling I06 and conduits I01 and 81 to the manifold 85. The chambers 3| and I02 communicate with each other exteriorally of the power cylinder 26 by means of a conduit I08 connected to the conduit 103 and to the sleeve 22 of the compensating relay valve I0. The diaphragm chamber [6 of the relay valve is connected to the control valve 90 through a conduit I09, coupling H0 and conduits III, H2 and 89 to the valve 90 and thence to the source of suction through the conduits 86 and 81 to the manifold 85.

In operation assume that the brakes are in release position, in this position the control valve 90 is open to provide communication between the conduits 86 and 89, whereby the piston 'I'I will be suspended in vacuum since the chambers 83 and 84 will then be in communication with the manifold 85. The relay valve is in the position shown in Fig. l to uncover the valve seat 35 whereby the chamber 3I in the power cylinder 26 is in communication with the source of suction through the port 25 in the relay valve, enlarged bore 2|, sleeve 22, conduit I08 and through conduit I03 to the manifold 85, and since the power cylinder chamber 3| is connected to the manifold 85 the diaphragm chamber I8 in the relay valve will also be exposed to suction through the by-pass 30 and power cylinder port 25, while the chamber I02 of the power cylinder 26 is at all times connected to the manifold 85 through the conduit I03, reservoir I04, conduit I05, coupling I06 and conduits I01 and 81. The diaphragm chamber I6 is exposed to vacuum through the conduit I09, coupling H0, conduits H2 and 89, control valve 90 and conduits 86 and 81 to the manifold 85. The valves 40 and 5| are maintained in brake release position when the diaphragm chambers I6 and I8 are exposed to suction since the air in the chamber II exerts atmospheric pressure against the diaphragms I4 and I5, but since the diaphragm I4 has the greatest effective area it pre' dominates over diaphragm I5 to move the valve 40 and 5! to the position shown in Fig. 1 and maintains the valves in this position without the use of springs.

In order to apply the brakes, pressure is exerted on the foot pedal 9I to operate the control valve 90 and interrupt communication between the conduits 89 and 86 to the manifold and permits atmosphere to enter the conduits 89 and 88 to the power chamber 84. The piston 11 is now unbalanced and. the atmosphere in the power cylinder chamber 84 moves the piston 11 to the left as seen in Fig. 3 to operate the rock shaft 80 and thus apply the brakes of the tractor wheels 82.

Atmosphere also enters from the control valve 90 through the conduits 89, H2 and III, coupling H0 and conduit I09 to the diaphragm chamber I6 in the relay valve. The diaphragm chamber I8 is still exposed to suction and accordingly the atmosphere now present in diaphragm chamber I6 causes the diaphragms I4 and I5 to move to the right as viewed in Fig. 1. This movement brings the valve 52 into sealing engagement with the resilient valve seat 35 to close oif the diaphragm chamber I8 and power cylinder chamber 3| to the source of suction. Continued movement of the diaphragms then causes the spring 55 to be compressed whereby the atmosphere valve 40 moves toward the seated valve 52 and the annular valve 4I uncovers the port 25 to bring the power cylinder chamber 3I into communication with the atmosphere through the air cleaner 24, port 23, annular recess 44 and port 25 to the power cylinder chamber 3|. The diaphragm chamber I8 is at the same time exposed to atmosphere through the by-pass 30 communicating with the port 25. In this brake applied position the suction in the conduit I08 tends to hold the valve 52 on its seat 35.

Should the operator reduce the pressure exerted on the foot pedal 9I so that the valve 90 is slightly open to the source of vacuum at the manifold 85, the pressure in the diaphragm chamber [6 will be reduced and the atmosphere present in the diaphragm chamber I1 will exert pressure on the diaphragm l4 and cause the latter to predominate over the diaphragm l5 to move the valve 40 only suificiently toward its valve seat 42 to close the port 25 whereby the valves 40 and 52 remain in lap position and the brakes will remain applied position.

In order to release the brakes, pressure is completely removed from the pedal 9|, the latter is moved to release position by a suitable retractor spring and the control valve 90 re-establishes communication between the conduits 86 and 89 with the manifold 85 whereby the chamber 84 of the power cylinder 16 is exposed to suction and the retractor spring 92 moves the tractor brakes to release position. The diaphragm chamber IS in the relay valve is also exposed to suction and accordingly the diaphragm I4 is subjected to differential pressure of vacuum and atmosphere to move the valves 42 and 52 into brake release position shown in Fig. 1 whereby the diaphragm chamber i8 and power cylinder chamber 3| are again exposed to the source of suction and the retractor spring I moves the piston 96 and the trailer wheel brakes to release position.

If desired, the trailer brakes may be actuated by a separate hand operated control valve H5 of the type shown in my aforesaid co-pending application. This valve is connected by conduits i it and I H, shown in dotted lines, to the conduit H2. In operation the control lever H8 is manipulated independently of the foot control valve 9b to control the admission of atmosphere to the diaphragm chamber IS in the relay valve to opere-to the valves 40 and 50 as will be understood.

Should the trailer accidentally separate from the tractor. air will be admitted into the trailer conduit Hi9 and thence into the diaphragm chamber it with consequent automatic brake application of the valves 40 and 50 and the trailer brakes in the manner hereinbefore described. A check valve not shown is provided in the conduit I65 to prevent entrance of air into the reservoir HM when the trailer breaks away from the tractor. The trailer brakes are maintained in brake applied position for a considerable length of time after this accidental separation because the valve 52 is seated on the resilient valve seat 35 to prevent entrance of atmosphere from the breather 24 and bore I9 to the manifold port 22 and thus through the conduits I08 and N13 to the reservoir I04 and power cylinder chamber iii? to thereby maintain the high degree of vacuum necessary to hold the trailer brakes in applied position.

It will be understood that various changes in the construction and arrangement of parts may be resorted to without departing from the scope of the appended claims.

I claim:

1. In a power brake system having a source of suction, a power cylinder to operate the brakes, a relay valve having a valve housing provided with a bore and ports communicating with said source of suction, power cylinder and the atmosphere, valve mechanism in said bore for controlling flow of the high and low pressure fluids to said power cylinder, a pair of spaced members responsive to differential pressure of vacuum and atmosphere to operate said valve mechanism, said spaced members defining a chamber between its adjacent sides at all times communicating with the atmosphere and defining variable pressure chambers between their opposite sides and said housing, means for at all times communicating one of said variable pressure chambers to said power cylinder, and a control valve for exposing the other of said variable pressure chambers to said source of suction and to the atmosphere.

2. In a power brake system having a source of suction, a power cylinder to operate the brakes, a relay valve having a valve housing provided with a bore and ports communicating with said source of suction, power cylinder and the atmosphere, valve mechanism in said bore for controlling fiow of the high and low pressure fluids to said power cylinder, a pair of spaced members of different elfective areas responsive to differential pressure of vacuum and atmosphere to operate said valve mechanism, said spaced members delining a chamber between its adjacent sides at all times communicating with the atmosphere and defining variable pressure chambers between their opposite sides and said housing, means for at all times communicating one of said variable pressure chambers to said power cylinder, and a control valve for exposing the other of said variable pressure chambers to said source of suction and to the atmosphere.

3. A valve for a power braking system, comprising a housing provided with a bore and ports for connection with the source of high pressure, brake cylinder and source of low pressure, valve mechanism in said bore including a first valve means for controlling communication between said brake cylinder port and high pressure port, and a second valve means directly controlled by the first valve means and movable with respect to said first valve means for controlling communication between said brake cylinder port and low pressure port, resilient means between said valve means for permitting said relative movement therebetween, and pressure responsive means connected to said valve mechanism and adapted to be exposed to high and low pressures to effect movement thereof and of said valve mechanism.

4. A valve for a power braking system, comprising a housing provided with a bore and ports for connection with the source of high pressure, brake cylinder, and source of low pressure, valve mechanism in said bore for controlling flow of fluid between said brake port, high pressure port and low pressure port, and a pair of spaced mem bers responsive to differential pressures to operate said valve mechanism, said spaced members defining a constant pressure chamber between them and defining variable pressure chambers between their opposite sides and said housing, one of which is at all times connected to said brake port.

5. In a power brake system having a source of suction, a power cylinder to operate the brakes, a relay valve having a valve housing provided with a bore and ports communicating with said source of suction, power cylinder and the atmosphere, valve mechanism in said bore for controlling flow of high and low pressure fluids to said power cylinder, an enlarged pressure differential chamber, a pair of spaced members therein having diiferent effective area and being responsive to differential pressure of vacuum and atmosphere to operate said valve mechanism, a chamber within said differential chamber and arranged be tween said members to communicate at all times with the atmosphere, and said pair of spaced members defining variable pressure chambers between themselves and said housing, means for at all times communicating one of said variable pressure chambers to said power cylinder, and a control valve for exposing the other of said variable pressure chambers to said source of suction and to the atmosphere.

6. In a power brake system having a source of suction, a power cylinder to operate the brakes, a relay valve having a valve housing provided with a bore and ports communicating with said source of suction, power cylinder and the atmosphere, valve mechanism in said bore for controlling flow of the high and low pressure fluids to said power cylinder, an enlarged pressure differential cham ber, a pair of spaced members therein having different effective areas and being responsive to differential pressure of vacuum and atmosphere to operate said valve mechanism, a chamber within said differential chamber and arranged between said members to communicate at all times with the atmosphere, the larger area member having one side exposed to constant pressure and the other side to variable pressures, the smaller area member having one side exposed to constant pressure and the other side to variable pressures, said pair of members defining variable pressure chambers between themselves and said housing, means for at all times communicating one of said variable pressure chambers to said power cylinder and a control valve for exposing the other of said variable pressure chambers tosaid source of suction and to the atmosphere.

7. In a power brake system having a source of suction, a power cylinder to operate the brakes, a relay valve having a valve housing provided with a bore and ports communicating with said source of suction, power cylinder and the atmosphere, a valve mechanism in said bore having a valve body for controlling the flow of high pressure fluid to said power cylinder, an auxiliary valve mounted in the valve body with a spring interposed between the two whereby movement of the valve body directly influences the auxiliary valve for controlling the flow of low pressure fluid to said cylinder, and pressure responsive means connected to said valve mechanism and adapted to be exposed to high and low pressures to eflect movement thereof and of said valve mechanism.

8. In a power brake system having a source of suction, a power cylinder to operate the brakes, a

relay valve having a valve housing provided with a bore and ports communicating with said source of suction, power cylinder and the atmosphere, a valve mechanism in said bore having a valve body for controlling the flow of high pressure fluid to said power cylinder, an auxiliary valve mounted in the valve body with a spring interposed between the two for controlling the flow of low pressure fluid to said cylinder, said valve housing having a pressure differential chamber, a pair of spaced members therein having different effec tive area and being responsive to differential pressure of vacuum and atmosphere to operate said valve mechanism, a chamber within said differential chamber arranged between said members to communicate at all times with the atmosphere, said spaced members defining variable pressure chambers between their opposite sides and said housing, and means for at all times communicating one of said variable pressure chambers to said brake port.

9. A valve for a power braking system comprising a housing provided with a bore and ports connecting with sources of high and low pressure and with a brake cylinder, a valve in said bore for controlling the flow through said ports, a pair of spaced members responsive to differential pressures to operate said valve, said spaced members defining a constant pressure chamber between their adjacent sides and defining variable pressure chambers between their opposite sides and said housing, one of said variable pressure chambers being exposed to a source of variable pressures, and pressure to the other of said variable pressure chambers being controlled by said valve and being at all times connected to said brake cylinder port.

10. A valve for power braking systems comprising a valve housing provided with a bore and parts connecting with sources of high and low pressure and with a brake cylinder, a variable pressure chamber formed at one end of said housing, said bore terminating at the other end of the housing in an enlarged valve chamber having resilient seats at opposite ends thereof, said valve chamber communicating with the brake cylinder port and said variable pressure chamber, a diaphragm in said variable pressure chamber, and a valve mechanism connected with said diaphragm and slidable in said bore for cooperation with the yiel-dable seats.

11. A valve for power braking systems comprising a housing provided with a bore and ports communicating with sources of high and low pressure and with a brake cylinder, a variable pressure chamber associated with said valve housing, a pressure responsive diaphragm mounted in said chamber, a valve mounted in said bore for controlling a pair of said ports, an auxiliary valve slidably mounted in the first valve for controlling the third port, and spring means interposed between the two valves.

GERHARD C. R. KUIPER, 

